Disk-based storage devices such as hard disk drives (HDDs) are commonly used to provide non-volatile data storage in a wide variety of different types of data processing systems. In such disk-based storage devices, a read channel typically sends Servo data to a disk controller over a 3-wire interface (up to 2 bits per cycle) or by requesting a register address over a standard Advanced Peripheral Bus (APB) or an Advanced High Performance Bus (AHB). A need remains for improved data interfaces for point-to-point communications between two devices, such as a read channel and a disk controller in an HDD system.